One of the teenagers accused of the Damilola Taylor murder repeatedly challenged police to prove he was at the scene of the killing, the Old Bailey heard.

The 16-year-old taunted police 10 times during questioning, but as the interview continued interrupted and said "Can you prove I was there at his death yes or no?".

One youth has walked free from the Old Bailey

Later the boy - 15 at the time of the interview - told the police he had not killed Damilola Taylor, but the court heard that officers thought the boy was hiding something.

The boy had been overheard concocting an alibi with his brother, also a suspect, the court was told.

Damilola, 10, died on November 27, 2000, from a thigh injury caused by a broken beer bottle on the North Peckham Estate, south London, where he lived.

The two boys and a third 15-year-old youth deny murder, manslaughter and assault with intent to rob.

A fourth boy - who had faced the same charges - walked free on Wednesday after Mr Justice Hooper directed the jury to find him not guilty, throwing out the evidence of a 14-year-old girl who claimed she had witnessed the killing.

'Threat'

A police officer told the trial he was abused by both brothers as he sat outside cells at a north London police station on 14 December 2000.

PC Stephen Humphrey, who wrote down portions of conversation he overheard, said he heard them making up a story about where they were on 27 November 2000 the day of the murder, the jury was told.

PC Humphrey told the Old Bailey on Thursday that he heard constant kicking and banging on cell doors and demands to be let out.

"They were shouting, swearing and threatening the police," the officer told the jury.

He had also noted rapping and singing coming from the two cells where the brothers, both aged 16, were being held, he added.

At one stage during the morning, the first brother, boy A, accused the officer of calling his mother a "bitch".

The boy placed his hands outside a hatch, made the sign of a gun with his fingers and said "boom", the officer told the court.

'They're no killers'

The second brother, boy B, spat through his cell hatch and allegedly told the officer: "I am going to have you when I get out".

PC Humphrey said he had heard Boy B say: "I can't believe we have been nicked for this. I can't remember where I was on the 27th."

On one occasion, when the boy was asked if he would "grass up" his brother who was also in custody, his mother told officers: "I know my sons and my sons ain't no killers."